/*
	mdfour.c

	An implementation of MD4 designed for use in the samba SMB
	authentication protocol

	Copyright (C) 1997-1998  Andrew Tridgell

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

	See the GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

	$Id: mdfour.c 7689 2007-11-12 14:28:40Z divverent $
*/

#include <string.h>				/* XoXus: needed for memset call */
#include "md4.h"

/* NOTE: This code makes no attempt to be fast!

   It assumes that a int is at least 32 bits long
*/

static struct mdfour *m;

#define F(X,Y,Z) (((X)&(Y)) | ((~(X))&(Z)))
#define G(X,Y,Z) (((X)&(Y)) | ((X)&(Z)) | ((Y)&(Z)))
#define H(X,Y,Z) ((X)^(Y)^(Z))
#ifdef LARGE_INT32
#define lshift(x,s) ((((x)<<(s))&0xFFFFFFFF) | (((x)>>(32-(s)))&0xFFFFFFFF))
#else
#define lshift(x,s) (((x)<<(s)) | ((x)>>(32-(s))))
#endif

#define ROUND1(a,b,c,d,k,s) a = lshift(a + F(b,c,d) + X[k], s)
#define ROUND2(a,b,c,d,k,s) a = lshift(a + G(b,c,d) + X[k] + 0x5A827999,s)
#define ROUND3(a,b,c,d,k,s) a = lshift(a + H(b,c,d) + X[k] + 0x6ED9EBA1,s)

/* this applies md4 to 64 byte chunks */
static void mdfour64(uint32 * M)
{
	int             j;
	uint32          AA, BB, CC, DD;
	uint32          X[16];
	uint32          A, B, C, D;

	for(j = 0; j < 16; j++)
		X[j] = M[j];

	A = m->A;
	B = m->B;
	C = m->C;
	D = m->D;
	AA = A;
	BB = B;
	CC = C;
	DD = D;

	ROUND1(A, B, C, D, 0, 3);
	ROUND1(D, A, B, C, 1, 7);
	ROUND1(C, D, A, B, 2, 11);
	ROUND1(B, C, D, A, 3, 19);
	ROUND1(A, B, C, D, 4, 3);
	ROUND1(D, A, B, C, 5, 7);
	ROUND1(C, D, A, B, 6, 11);
	ROUND1(B, C, D, A, 7, 19);
	ROUND1(A, B, C, D, 8, 3);
	ROUND1(D, A, B, C, 9, 7);
	ROUND1(C, D, A, B, 10, 11);
	ROUND1(B, C, D, A, 11, 19);
	ROUND1(A, B, C, D, 12, 3);
	ROUND1(D, A, B, C, 13, 7);
	ROUND1(C, D, A, B, 14, 11);
	ROUND1(B, C, D, A, 15, 19);

	ROUND2(A, B, C, D, 0, 3);
	ROUND2(D, A, B, C, 4, 5);
	ROUND2(C, D, A, B, 8, 9);
	ROUND2(B, C, D, A, 12, 13);
	ROUND2(A, B, C, D, 1, 3);
	ROUND2(D, A, B, C, 5, 5);
	ROUND2(C, D, A, B, 9, 9);
	ROUND2(B, C, D, A, 13, 13);
	ROUND2(A, B, C, D, 2, 3);
	ROUND2(D, A, B, C, 6, 5);
	ROUND2(C, D, A, B, 10, 9);
	ROUND2(B, C, D, A, 14, 13);
	ROUND2(A, B, C, D, 3, 3);
	ROUND2(D, A, B, C, 7, 5);
	ROUND2(C, D, A, B, 11, 9);
	ROUND2(B, C, D, A, 15, 13);

	ROUND3(A, B, C, D, 0, 3);
	ROUND3(D, A, B, C, 8, 9);
	ROUND3(C, D, A, B, 4, 11);
	ROUND3(B, C, D, A, 12, 15);
	ROUND3(A, B, C, D, 2, 3);
	ROUND3(D, A, B, C, 10, 9);
	ROUND3(C, D, A, B, 6, 11);
	ROUND3(B, C, D, A, 14, 15);
	ROUND3(A, B, C, D, 1, 3);
	ROUND3(D, A, B, C, 9, 9);
	ROUND3(C, D, A, B, 5, 11);
	ROUND3(B, C, D, A, 13, 15);
	ROUND3(A, B, C, D, 3, 3);
	ROUND3(D, A, B, C, 11, 9);
	ROUND3(C, D, A, B, 7, 11);
	ROUND3(B, C, D, A, 15, 15);

	A += AA;
	B += BB;
	C += CC;
	D += DD;

#ifdef LARGE_INT32
	A &= 0xFFFFFFFF;
	B &= 0xFFFFFFFF;
	C &= 0xFFFFFFFF;
	D &= 0xFFFFFFFF;
#endif

	for(j = 0; j < 16; j++)
		X[j] = 0;

	m->A = A;
	m->B = B;
	m->C = C;
	m->D = D;
}

static void copy64(uint32 * M, unsigned char *in)
{
	int             i;

	for(i = 0; i < 16; i++)
		M[i] = (in[i * 4 + 3] << 24) | (in[i * 4 + 2] << 16) | (in[i * 4 + 1] << 8) | (in[i * 4 + 0] << 0);
}

static void copy4(unsigned char *out, uint32 x)
{
	out[0] = x & 0xFF;
	out[1] = (x >> 8) & 0xFF;
	out[2] = (x >> 16) & 0xFF;
	out[3] = (x >> 24) & 0xFF;
}

void mdfour_begin(struct mdfour *md)
{
	md->A = 0x67452301;
	md->B = 0xefcdab89;
	md->C = 0x98badcfe;
	md->D = 0x10325476;
	md->totalN = 0;
}


static void mdfour_tail(unsigned char *in, int n)
{
	unsigned char   buf[128];
	uint32          M[16];
	uint32          b;

	m->totalN += n;

	b = m->totalN * 8;

	memset(buf, 0, 128);
	if(n)
		memcpy(buf, in, n);
	buf[n] = 0x80;

	if(n <= 55)
	{
		copy4(buf + 56, b);
		copy64(M, buf);
		mdfour64(M);
	}
	else
	{
		copy4(buf + 120, b);
		copy64(M, buf);
		mdfour64(M);
		copy64(M, buf + 64);
		mdfour64(M);
	}
}

void mdfour_update(struct mdfour *md, unsigned char *in, int n)
{
	uint32          M[16];

// start of edit by Forest 'LordHavoc' Hale
// commented out to prevent crashing when length is 0
//  if (n == 0) mdfour_tail(in, n);
// end of edit by Forest 'LordHavoc' Hale

	m = md;

	while(n >= 64)
	{
		copy64(M, in);
		mdfour64(M);
		in += 64;
		n -= 64;
		m->totalN += 64;
	}

	mdfour_tail(in, n);
}


void mdfour_result(struct mdfour *md, unsigned char *out)
{
	m = md;

	copy4(out, m->A);
	copy4(out + 4, m->B);
	copy4(out + 8, m->C);
	copy4(out + 12, m->D);
}


void mdfour(unsigned char *out, unsigned char *in, int n)
{
	struct mdfour   md;

	mdfour_begin(&md);
	mdfour_update(&md, in, n);
	mdfour_result(&md, out);
}

///////////////////////////////////////////////////////////////
//  MD4-based checksum utility functions
//
//  Copyright (C) 2000       Jeff Teunissen <d2deek@pmail.net>
//
//  Author: Jeff Teunissen  <d2deek@pmail.net>
//  Date: 01 Jan 2000

unsigned Com_BlockChecksum(void *buffer, int length)
{
	int             digest[4];
	unsigned        val;

	mdfour((unsigned char *)digest, (unsigned char *)buffer, length);

	val = digest[0] ^ digest[1] ^ digest[2] ^ digest[3];

	return val;
}

void Com_BlockFullChecksum(void *buffer, int len, unsigned char *outbuf)
{
	mdfour(outbuf, (unsigned char *)buffer, len);
}
